Mobility in a multi-access communication network

ABSTRACT

Various embodiments provide a terminal capable of establishing multiple communication sessions with a public network proxy through different access networks. The terminal actively communicates with the public network proxy to control which of the multiple communication paths are active, as well as control the transition from actively using one communication path to using another. The public network proxy facilitates data and voice sessions between the terminal and any number of other communication devices. In one embodiment, the communication sessions are reserved tunneling sessions, and the terminal cooperates with the public network proxy to effectively control how many tunneling sessions are established, how many tunneling sessions are active at any given time, and the transition from one tunneling session to another for active communications. Each of the communication or tunneling sessions may be established over different access networks using different communication technologies and protocols.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 12/685,486, filed Jan. 11, 2010, entitled “Mobilityin a Multi-Access Communication Network,” which is a continuation of andclaims priority to U.S. patent application Ser. No. 10/628,167, now U.S.Pat. No. 7,646,710, filed on Jul. 28, 2003, the content of each of whichis hereby incorporated herein by reference.

BACKGROUND

The present invention relates to communications, and in particular toallowing a mobile terminal to communicate with other communicationdevices via disparate access networks.

Expansion of packet-based networks, such as the Internet, is extendinginto mobile environments. Accordingly, mobile terminals equipped withwireless communication capability can now establish communicationsessions with other communication devices in part over wirelesscommunication channels. Unfortunately, there are numerous wirelesscommunication networks using different communication technologies andprotocols. In an effort to increase functionality, these mobileterminals may be equipped to communicate with different types ofnetworks using the same or different access technologies. With suchcapabilities, there is a need for an efficient technique to allow themobile terminals to communicate with the other communication devicesover different access networks. There is a further need for an effectivetechnique to transition through sequential connections over thesedifferent access networks as the user element moves from one accessnetwork to another.

SUMMARY

The present invention provides a terminal with the capability ofestablishing multiple communication sessions with a public network proxythrough different access networks. The terminal can actively communicatewith the public network proxy to control which of the multiplecommunication paths are active, as well as control the transition fromactively using one communication path to using another. The publicnetwork proxy will facilitate communications between the terminal andany number of other communication devices to facilitate data or voicesessions. In one embodiment, the communication sessions are reservedtunneling sessions, and the terminal cooperates with the public networkproxy to effectively control how many tunneling sessions areestablished, how many tunneling sessions are active at any given time,and the transition from one tunneling session to another for activecommunications. Each of the communication or tunneling sessions may beestablished over different access networks using different communicationtechnologies and protocols.

Those skilled in the art will appreciate the scope of the presentinvention and realize additional aspects thereof after reading thefollowing detailed description of the preferred embodiments inassociation with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a block representation of a communication environmentaccording to one embodiment of the present invention.

FIG. 2 is a flow diagram illustrating basic operation of a mobileterminal according to one embodiment of the present invention.

FIG. 3 is a block representation of a public network proxy according toone embodiment of the present invention.

FIG. 4 is a block representation of a mobile terminal according to oneembodiment of the present invention.

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the invention and illustratethe best mode of practicing the invention. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the invention and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure and the accompanying claims.

The present invention allows a mobile terminal to effectively controlthe paths through which it will communicate with a public network proxy,which facilitates communications with any number of communicationdevices for data or voice applications. The different communicationpaths to the public network proxy may be supported by different accessnetworks using different communication technologies and protocols. Inoperation, the mobile terminal will take the necessary steps toestablish communication paths and determine which of these communicationpaths will be active and facilitate the transmission and reception ofpackets to and from the public network proxy. A decision between twoavailable communication paths may be based on cost or performancecharacteristics. Based on instructions from the mobile terminal, thepublic network proxy will take the necessary steps to facilitatecommunications between the appropriate communication devices and themobile terminal over the active communication path or paths, as well asfacilitate handoffs from one access network to another. The handoffswill preferably be initiated by the mobile terminal via instructionssent to the public network proxy. Further, multiple communication pathsmay be active at the same time, wherein duplicate packets aresimultaneously sent over different communication paths. Alternatively,the multiple communication paths may be used to increase transfer rates.In one embodiment, the communication paths are tunneling sessionsestablished between the mobile terminal and the public network proxy viathe various access networks using any number of tunneling protocols,such as through one or more Internet Protocol (IP) Security (SEC)connections or virtual private networks (VPNs).

To the correspondent communication devices, the mobile terminal will beassociated with a public IP address, which is supported by the publicnetwork proxy. As such, packets sent to the mobile terminal will be sentto the public network proxy using the public IP address of the mobileterminal. Depending on the access network through which the mobileterminal can be reached by the public network proxy, different temporaryIP addresses will be assigned to the mobile terminal for the variousaccess networks. The public network proxy will use the appropriatetemporary IP address for forwarding the packets received from thecommunication devices on to the mobile terminal within the confines ofthe tunneling protocols. In return, the mobile terminal will encapsulatepackets intended for the communication devices using the appropriatetunneling protocols, which effects delivery of the packets initially tothe public network proxy, which will extract the original packets andforward them as necessary to the communication devices. Again, thepackets transferred between the mobile terminal and the communicationdevices through the public network proxy may include voice or data, thelatter of which may include virtually any type of information, audio, orvideo.

With reference to FIG. 1, a communication environment 10 according tothe present invention is illustrated, wherein the mobile terminal 14 iscapable of communicating with numerous communication devices 16 with theaid of the public network proxy 12. The mobile terminal 14 may be anyportable device capable of facilitating communications via multipleaccess networks. Examples include personal computers, personal digitalassistants, mobile telephones, or any other device benefiting fromcommunicating with remote communication devices. In general, the publicnetwork proxy 12 and the communication devices 16 are directly orindirectly coupled to a packet network 18, which is further coupled tonumerous access networks 20. These access networks 20 may supportvarious wired or wireless communications with the mobile terminal 14,depending on the communication capabilities of the mobile terminal 14.As illustrated for exemplary purposes only, there are four accessnetworks 20 operatively coupled to the packet network 18, wherein eachaccess network 20 supports one of the following communicationtechnologies: local wireless (Bluetooth), wireless local area network(WLAN), cellular, and traditional wired Ethernet. Although only one ofeach type of access network 20 is illustrated, there may be multipleaccess network 20 providing disparate or overlapping coverage. For eachof the access networks 20, an access point 22 that is capable ofproviding the actual wired or wireless communication link to the mobileterminal 14 is provided. For the Bluetooth and WLAN access networks 20,the access points 22 may be a simple Bluetooth or WLAN modem, which iscapable of providing bi-directional wireless communications with themobile terminal 14. The access point or points for a cellular accessnetwork 20 is generally a cellular network of base stations 24 operatingin traditional fashion. Further, the Ethernet-based access network 20will have an access point 22 capable of supporting a wired Ethernetconnection.

Regardless of the communication technology incorporated by the accessnetwork 20 and associated access point 22, the mobile terminal 14 iscapable of establishing communications with the access network 20 viathe access points 22 (or base stations 24), and ultimately with thepublic network proxy 12 via the packet network 18 using any availablecommunication protocol, and preferably a tunneling protocol toeffectively define a communication path between the mobile terminal 14and the public network proxy 12.

In operation, the mobile terminal 14 is capable of establishingtunneling sessions through multiple ones of the access networks 20 ascommunication capability permits. As such, at any given time, the mobileterminal 14 may have multiple tunneling sessions through whichcommunications with the public network proxy 12 can be supported. Withreference now to FIG. 2, a flow diagram is provided to illustrate howcommunications between the mobile terminal 14 and the public networkproxy 12 are established and controlled predominantly by the mobileterminal 14.

Initially, the mobile terminal 14 will establish layer 2 and 3connectivity with one or more available access networks 20 via therespective access points 22 (which include the base stations 24) (step100). Although the flow diagram of FIG. 2 focuses on using twoconnections, the invention is applicable for any number of connections.Further, each connection may be fully separate in setup and functionwith respect to other connections. The access networks 20 will recognizethe connectivity and the packet capability of the mobile terminal 14 andprovide temporary IP addresses, designated IP₁ and IP₂, for the WLAN andcellular access networks 20, respectively, and send the temporary IPaddresses IP₁ and IP₂ to the mobile terminal 14. The mobile terminal 14will receive the temporary IP addresses IP₁ and IP₂ from the respectiveaccess networks 20 (step 102), and establish tunneling sessions with thepublic network proxy 12 through each access network 20 using therespective temporary IP addresses (step 104). Notably, the communicationdevices 16 will use the primary address for the mobile terminal 14,IP_(p), to send packets toward the mobile terminal 14, wherein thepackets will actually be received by the public network proxy 12 onbehalf of the mobile terminal 14.

At this point, the mobile terminal 14 has established two tunnelingsessions, referenced as 26 and 28 in FIG. 1. In one embodiment, themobile terminal 14 will select a first tunneling session to be an activetunneling session (step 106) and notify the public network proxy 12 ofthe selection of the first tunneling session as the primary tunnelingsession (step 108). Such selection may be accomplished in many ways. Forexample, the mobile terminal 14 may establish multiple IP Security(IPSec) tunnels using the same credentials. The public network proxy 12will recognize it as the same client. Then, by choosing to send theoutbound packets over one tunnel, it will be defined as the activetunnel. If the mobile terminal 14 uses both tunnels to send packets,then the tunnels are in a load-sharing mode for increased bandwidth. Ifthe mobile terminal 14 uses both tunnels to send identical packets, thenthe mobile terminal 14 is using the two channels for improvedreliability or to begin the process of transitioning from one tunnelbeing active to the other. Although the second tunneling session isavailable, the mobile terminal 14 and the public network proxy 12 willoperate to send and receive packets via the first tunneling session 26using the first temporary IP address, IP₁ (step 110). In the background,the public network proxy 12 will forward packets received from themobile terminal 14 to the appropriate communication device 16, as wellas receive packets from the communication devices 16 and forward them tothe mobile terminal 14 using the first temporary IP address IP₁ withinthe first tunneling session 26.

At some point, assume that the mobile terminal 14 detects a need totransition to the second tunneling session 28 from the first tunnelingsession 26 due to observed communication errors, transmission rates,quality of service issues, or desired service plans (step 112).Accordingly, the mobile terminal 14 will notify the public network proxy12 of the need to transition to the second tunneling session 28 througheither of the first or second tunneling sessions 26, 28 (step 114). Atthis point, the public network proxy 12 may begin a transition phase,wherein the mobile terminal 14 and public network proxy 12 send andreceive packets via the first and second tunneling sessions 26, 28 usingthe respective temporary IP addresses, IP₁ and IP₂ (step 116). Such atransition is beneficial to prevent a break in voice or streaming mediaservices. During this transition or handoff, duplicate packets may besent over the first and second tunneling sessions 26, 28, and thereceiving entity, either the public network proxy 12 or the mobileterminal 14, may simply monitor packet header information, such assequence numbering, to determine whether a packet is a duplicate packetof one which has already been received.

At some point during the transition period, the mobile terminal 14 willdetect the desirability to stop using or the inability to use the firsttunneling session 26 (step 118). The mobile terminal 14 may directly orindirectly notify the public network proxy 12 of the permanent selectionof the second tunneling session 28 (step 120), by sending a signal or byno longer using or being able to use the connection. Thus, notificationmay be simply a recognition that the connection is no longer availableor in use. The packets are then sent and received only via the secondtunneling session 28 using the second temporary IP address, IP₂ (step122).

In addition to selecting a first tunneling session 26 and transitioningas necessary to a second tunneling session 28 during handoffs betweenone access network 20 and another, the mobile terminal 14 can controlthe use of the multiple tunneling sessions in any desired fashion,wherein duplicate packets may be sent over the multiple tunnelingsessions to improve communication resiliency and increase quality ofservice, as well as have different packets sent over the differenttunneling sessions to increase effective transfer rates between thepublic network proxy 12 and the mobile terminal 14 in either direction.The mobile terminal 14 will effectively control the public network proxy12 to determine when and how packets are sent and when handoffs from onetunneling session to another occur. Further, the mobile terminal 14 candecide how many tunneling sessions should be established, and how manyof those established tunneling sessions are active. Accordingly,multiple tunneling sessions may be available at any given time, but onlyone or more of those tunneling sessions may be in active use. An activemanagement system can be used to establish multiple tunnelsindependently and manage them in a desired fashion. As an example, theSession Initiation Protocol (SIP) may be used to enable a single sessionto have multiple streams. These streams can be added and removed andhave attributes such as Codec, frame size, and the like. Any tunnel orconnection could be used to carry the SIP messages, and the streamdefinitions could be modified to define which are active and whetherthey are in redundant or bandwidth augmentation mode.

Turning now to FIG. 3, a block diagram of a public network proxy 12 isillustrated. The public network proxy 12 will preferably include acontrol system 32, which may include a central processing unit (CPU),having sufficient memory 34 to store the software 36 necessary foroperation as described above. The control system 32 is also associatedwith one or more packet interfaces 38 to facilitate communications withthe various communication devices 16 and the access networks 20.

Those skilled in the art will recognize the numerous forms the mobileterminal 14 may take. The basic communication architecture of the mobileterminal 14 is represented in FIG. 4 and includes a receiver front end40, a radio frequency transmitter section 42, an antenna 44, a duplexeror switch 46, a baseband processor 48, a control system 50, a frequencysynthesizer 52, and an interface 54. The receiver front end 40 receivesinformation bearing radio frequency signals from one or more remotetransmitters provided by a base station. A low noise amplifier 56amplifies the signal. A filter circuit 58 minimizes broadbandinterference in the received signal, while downconversion anddigitization circuitry 60 downconverts the filtered, received signal toan intermediate or baseband frequency signal, which is then digitizedinto one or more digital streams. The receiver front end 40 typicallyuses one or more mixing frequencies generated by the frequencysynthesizer 52. The baseband processor 48 processes the digitizedreceived signal to extract the information or data bits conveyed in thereceived signal. This processing typically comprises demodulation,decoding, and error correction operations. As such, the basebandprocessor 48 is generally implemented in one or more digital signalprocessors (DSPs).

On the transmit side, the baseband processor 48 receives digitized data,which may represent voice, data, or control information, from thecontrol system 50, which it encodes for transmission. The encoded datais output to the transmitter 42, where it is used by a modulator 62 tomodulate a carrier signal that is at a desired transmit frequency. Poweramplifier circuitry 64 amplifies the modulated carrier signal to a levelappropriate for transmission, and delivers the amplified and modulatedcarrier signal to the antenna 44 through the duplexer or switch 46.

As noted above, the mobile terminal 14 must be able to communicate withmultiple ones of the access networks 20 via the various access points22, which are generally defined to include the network of base stations24. Accordingly, the receiver front end 40, baseband processor 48, andradio frequency transmitter section 42 cooperate to provide one or moreof the following interfaces: Bluetooth (or other local wirelessinterface), WLAN, or cellular. Further, an Ethernet interface 66 may beprovided for a more traditional wired connection to a correspondingaccess network 20. Wireless communication capability may be implementedusing redundant circuitry, or by configuring common circuitry to operatein different modes. The configuration of the mobile terminal 14 will bedictated by economics and designer choice. The mobile terminal 14 isconfigured such that the proper mode of operation is selected by thecontrol system 50, which will also implement the necessary protocols andpacket processing for the various communication technologies. As notedabove, the above communication circuitry is preferably configured toeffectively communicate in different modes at the same time. Further, auser may interact with the mobile terminal 14 via the interface 54,which may include interface circuitry associated with a microphone, aspeaker, a keypad, and a display.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present invention. All suchimprovements and modifications are considered within the scope of theconcepts disclosed herein and the claims that follow.

What is claimed:
 1. A mobile device for managing multiple flows ofcommunications packets over a plurality of access networks comprising:communication circuitry that facilitates communications with theplurality of access networks; and a control system associated with thecommunication circuitry configured to: establish a first communicationssession, via a first access network, with a network proxy; establish asecond communications session, via a second access network with thenetwork proxy; route the communications packets through the firstcommunications session; transition a flow of a first portion of thecommunications packets from the first communications session to thesecond communications session; and route the first portion ofcommunications packets through the first communications session, androute a second portion of the communications packets through the secondcommunications session; wherein the routing the first portion ofcommunications packets through the first communications session and therouting the second portion of the communications packets through thesecond communications session increases the transfer rate of thecommunications packets.
 2. The mobile device of claim 1, wherein thefirst portion of the communications packets and the second portion ofthe communications packets are different.
 3. The mobile device of claim1, wherein the first portion of the communications packets and thesecond portion of the communications packets are identical.
 4. Themobile device of claim 1, wherein the first portion and second portionof the communications packets are communicated simultaneously over thefirst and second communications sessions.
 5. The mobile device of claim1, wherein a decision to perform the transition is based on cost orquality of service characteristics.
 6. The mobile device of claim 1, thecontrol system further configured to: discontinue use of the firstaccess network after the transition to the second access network.
 7. Themobile device of claim 1, wherein the control system is furtherconfigured to cause the communications packets to be routed over apacket network to communications devices comprising voice and dataapplications.
 8. The mobile device of claim 7, wherein the first portionof the communications packets and the second portion of thecommunications packets are associated with a same voice or dataapplication.
 9. The mobile device of claim 7, wherein the first portionof the communications packets and the second portion of thecommunications packets are associated with different voice or dataapplications.
 10. The mobile device of claim 1, wherein the first accessnetwork is a cellular access network.
 11. The mobile device of claim 1,wherein the second access network is a wireless local area network(WLAN) or a cellular access network.
 12. A method for switching multipleflows of communications packets between a mobile device and multipleaccess networks, the method comprising: establishing a firstcommunications session between the mobile device and a first accessnetwork of the multiple access networks; establishing a secondcommunications session between the mobile device and a second accessnetwork of the multiple access networks; routing a flow of thecommunications packets through the first communications session;deciding to transition a flow of a first portion of the communicationspackets from the first communications session to the secondcommunications session; and routing the first portion of communicationspackets through the first communications session, and routing a secondportion of the communications packets through the second communicationssession; wherein the routing the first portion of communications packetsthrough the first communications session and the routing the secondportion of the communications packets through the second communicationssession increases the transfer rate of the communications packets. 13.The method of claim 12, wherein the deciding to perform the transitionis performed by the mobile device.
 14. The method of claim 12, whereinthe deciding to perform the transition is based on a servicecharacteristic.
 15. The method of claim 14, wherein the deciding toperform the transition is based on a service characteristic related tocost.
 16. The method of claim 15, wherein the deciding to perform thetransition, based on the service characteristic related to cost, isperformed by the mobile device.
 17. The method of claim 14, wherein thedeciding to perform the transition is based on the servicecharacteristic related to quality of service.
 18. The method of claim17, wherein the deciding to perform the transition, based on the servicecharacteristic related to quality of service, is performed by the mobiledevice.
 19. The method of claim 17, wherein the service characteristicrelated to quality of service is an observed characteristic ofcommunication errors, transmission rates, or quality of service issues.20. The method of claim 19, wherein the observed characteristic ofcommunication errors, transmission rates, or quality of service issuesis observed by the mobile device.
 21. The mobile device of claim 3,wherein the identical portions of the communications packets are routedthrough the first communication session and the second communicationsession to facilitate a handoff.